nginx配置多个应用通过80端口访问

upstream www.a.com {
    server localhost:8080;
}
upstream pan.a.com {
    server localhost:8081;
}

server {
    listen 80;
    server_name www.a.com;
    location / {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://www.a.com;
    }
}
server {
    listen 80;
    server_name pan.a.com;
    location / {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://pan.a.com;
    }
}

upstream admin_server{
    server a.com:8080;
}
upstream product_server{
    server a.com:8081;
}
 
server {
    listen 80;
    server_name a.com;
    location /product/ {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://product_server/;
}
 
location /admin/ {
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass http://admin_server/;
}
}